1. Field of the Invention
The present invention relates to image display apparatuses suited to a viewfinder which is connected to a TV camera and used for focusing and other purposes.
2. Description of the Related Art
A camera operator uses the viewfinder of a TV camera in a studio of a broadcasting station for focusing and checking a composition. At a side of the viewfinder of the TV camera, a lamp called a tally lamp is provided.
This tally lamp indicates which TV camera is being used in broadcasting when a TV screen is formed by switching the images sent from a plurality of TV cameras. In general, two tally lamps are provided for a TV camera, one for the cast at a position where the cast can easily see it from the front side of the TV camera, such as the top of the center of the TV camera, and the other for the camera operator at a position where the camera operator can easily see, such as the side of the viewfinder.
Therefore, a camera operator can understand from the on state of the tally lamp of the TV camera the operator manipulates whether the TV camera is being selected as the camera sending the image used for the actual TV screen even while a plurality of TV cameras take images of the cast.
In a TV camera used in a broadcasting station, generally, a viewfinder is formed of a cathode-ray tube (CRT); and a tally lamp is formed of a high-luminance light-emitting diode (LED) and mounted on an image frame provided outside the screen of the viewfinder, separately from the screen.
Since it is strongly demanded in recent years that TV cameras used in a broadcasting station be made compact and lightweight, viewfinders have been formed of liquid-crystal apparatuses to make the viewfinders more compact and thinner. Even when the viewfinders are made more compact and thinner with the use of liquid-crystal apparatuses, however, since the LEDs used for tally lamps are about 6 mm thick, the viewfinders become thick by the thickness of the tally lamps, which prevents the viewfinders from being thinner and more compact.
Red and green tally lamps are usually used for this purpose, and different colors indicate different meanings. If the colors of tally lamps need to be changed due to the demand of the user to a color other than red and green, since the colors of LEDs are limited, tally lamps having various colors cannot be prepared. In addition, tally lamps formed of LEDs just indicate the on and off states of red or green lamps, and cannot indicate character information.
Depending on the surrounding environment of a place where these tally lamps are used, it may be difficult to identify the on states of the lamps, or conversely, the lamps may become obstacles due to their high luminance. Therefore, it is necessary to make the luminance variable according to the surrounding environment of use, but to increase the luminance of the tally lamps formed of LEDs, the voltage applied thereto needs to be increased, which increases power consumption.
The present invention has been made in consideration of the above conditions. Accordingly, an object of the present invention is to provide an image display apparatus which provides a sub display area that can serve as a tally lamp to eliminate a tally lamp formed of a LED, which has been conventionally required; which allows a viewfinder provided with the function of a tally lamp to be made thinner; and which also allows power consumption to be reduced. Another object of the present invention is to provide an image display apparatus which allows a sub display area to display character information and image information.
One of the foregoing objects is achieved according to the present invention through the provision of an image display apparatus including a main display area having a plurality of pixels arranged horizontally and vertically in an array condition; at least one sub display area disposed separately from the main display area and having a plurality of pixels arranged horizontally and vertically in an array condition; a plurality of lines arranged horizontally and vertically in a matrix manner against the main display area and the sub display area for driving the plurality of pixels; and driving means for applying a driving signal to the plurality of lines disposed in the matrix manner.
Since the driving means can send a signal other than an image signal to be displayed on the main display area to the at least one sub display area formed outside the main display area, information substituting for the display of a tally lamp can be indicated on the sub display area. Unlike a case in which an LED lamp is separately provided, since the sub display area is formed outside the main display area on the same plane as the main display area, the image display apparatus does not need to be thick. Therefore, even when the sub display area is provided, the image display apparatus does not become thicker than required.
In addition, when the transmittance of the liquid crystal in the sub display area is made variable separately from the main display area, with the use of a dimmer control signal, the luminance of the sub display area can be adjusted to a level suited to the surrounding environment of use without increasing power consumption.
In the present invention, pixels disposed at the outer periphery of the main display area may be used for displaying an image frame.
When the pixels used for displaying the image frame are driven separately from those used for displaying an image, the boundary between the main display area and the sub display area can be easily understood by the user as the image frame, and the distinction between the sub display area and the main display area can be easily made.
When the main display area and the sub display are made in a liquid-crystal display apparatus, an image display apparatus that provides the thinness and compactness which the liquid-crystal display apparatus inherently possesses and that allows the sub display area to function as a tally lamp is provided. Further, when the sub display area is driven through the lines therefor, character information and image information can be displayed on the sub display area. Therefore, in addition to the single-color turning-on display function which the conventional tally lamp fulfills, a desired indicator, character information, or image information can be displayed as information separated from that shown on the main display area. When the liquid-crystal display apparatus drives pixels by the use of thin-film transistors, the sub display area provides quick response.
Furthermore, in the present invention, luminance-signal control means for controlling the luminance of the sub display area may be provided for the image display apparatus.
In the present invention, the main display area and the sub display area may be formed of an active-matrix liquid-crystal display panel.
In the present invention, the main display area and the sub display area may be formed of a passive-matrix liquid-crystal display panel.